Clitoral vascular engorgement plays an important role in female sexual desire, arousal and satisfaction. Sexual arousal results in smooth muscle relaxation and arterial vasodilation within the clitoris. The resultant increase in blood flow leads to tumescence of the glans clitoris and increased sexual arousal. A variety of conditions may cause clitoral erectile insufficiency and reduced clitoral arterial flow. This, in turn, may lead to difficulty or inability to achieve clitoral tumescence. Female sexual wellness may also be negatively affected by a lack of subjective excitement, genital lubrication or orgasmic function.
The incidence of symptoms ranging from dissatisfaction to dysfunction is high in women. For example, in the National Health and Social Life Survey of 1,749 women age 18-59, 43% experienced sexual. Further, female sexual dysfunction is altered with aging, is progressive and highly prevalent affecting 30-50% of women and 68 to 75% of women experience sexual dissatisfaction or “problems” (not dysfunctional in nature). In a national survey of more than 31,000 women in the United States, 44.2% of women reported experiencing a sexual problem. According to other studies, over 53 million women (43% of the U.S. population) have reported one or more sexual problems and over 14 million women meet the clinical criteria for Female Sexual Dysfunction (FSD), with low desire being by far the most common problem (reported by 46 million women). (See, e.g., Spector I, Carey M. Incidence and prevalence of the sexual dysfunctions: a critical review of the empirical literature. 19: 389-408, 1990; Rosen R C, Taylor J F, Leiblum S R, et al: Prevalence of sexual dysfunction in women: results of a survey study of 329 women in an outpatient gynecological clinic. J. Sex. Mar. Ther. 19:171-188, 1993; Read S, King M, Watson J: Sexual dysfunction in primary medical care: prevalence, characteristics and detection by the general practitioner. J. Public Health Med. 19:387-391, 1997; Laumann E, Paik A, Rosen R. Sexual Dysfunction in the United States Prevalance and Predictors. JAMA, 1, 281: 537-544; Read S, King M, Watson J. Sexual dysfunction in primary medical care: prevalence, characteristics and detection by the general practitioner. J Public Health Med. 1997; 19:387-91; Schein M, Zyzanski S J, Levine S, Medalie J H, Dickman R L, Alemagno S A. The frequency of sexual problems among family practice patients. Fam Pract Res J. 1988; 7:122-34; Shifren J L, Monz B U, Russo P A, Segreti A, Johannes C B. Sexual problems and distress in United States women: prevalence and correlates. Obstet Gynecol. 2008; 112(5):970-978; and Shifren, Obstet Gynecol 2008; 112: 970-8. Each of these publications is incorporated by reference herein.)
Research indicates that a sufficient blood supply is required for good clitoral and vaginal function and satisfying sexual experience at any age. Women at risk for Female Sexual Dysfunction include those using birth control pills, those with poor vascular health (such as those with diabetes, high cholesterol, or hypertension), aging women and those undergoing or having undergone cancer radiation treatment (which may adversely decrease lubrication, hormone levels, and/or genital sensation). Using birth control pills can lower the circulating levels of testosterone needed to regulate blood flow to genitals and stimulate sexual desire and can cause long-term permanent sex hormone insufficiency. Also, the prevalence of sexual problems increases dramatically by age, with 27.2% of women aged 18 to 44 years, 44.6% of women aged 45 to 64 years, and 80.1% of women aged 65 years and older reporting sexual problems.
While the majority of male and female sexual organ is similar, a subtle anatomical difference makes females more susceptible to inhibitors. While the glans penis in men and the glans clitoris in women similarly each have the highest concentration of sensory receptors than any other location in the body, the male anatomy provides more extensive structural support for the glans penis. Addressing male sexual dysfunction can take advantage of this structural support by augmenting or enhancing the venous trapping function of the corpus cavernosum. In contrast, no anatomical sustain mechanism exists in women for engorgement making women more susceptible to an array of powerful inhibitors. While the female corpus canvernosum does become engorged during stimulation (see FIG. 29), it does not sustain engorgement to the same degree as the male anatomy.
FIG. 30 illustrates the variety of factors that can act as inhibitors or promoters of sufficient sexual stimulation. For example, FIG. 30 illustrates how sensory and psychosocial factors, such as the well-being of the woman's relationship with her partner and emotional or visual cues, drive central nervous system (CNS) mediated promotion or inhibition (denoted by the +/− symbol). Other health factors such as diabetes or cardiovascular disease or factors such as drugs can drive other inhibition or promotion. This multifactorial web has made developing a safe drug for treating women very challenging.
The female sexual response cycle affects the incidence of a satisfying sexual experience (SSE) for women. The cycle includes the states of (i) emotional and physical satisfaction, leading to (ii) emotional intimacy, leading to (iii) being receptive to sexual stimuli, leading to (iv) sexual arousal, leading to (v) arousal and sexual desire, which takes the cycle back around to the state of (i) emotional and physical satisfaction. Spontaneous sex drive can occur between states (ii) and (iii), between states (iii) and (iv), and/or between states (iv) and (v).
These and other challenges can be addressed by embodiments of the present invention.